1. Field of the Invention
The present invention relates to a safety device for a passenger conveyor such as an escalator or a moving walk, which immediately stops its operation when a passenger's leg or a foreign object is caught in a clearance between a passenger step and a combplate provided at the landing of the passenger conveyor.
More particularly, the present invention relates to a combplate safety device for the passenger conveyor, wherein the combplate can be displaced in two directions, that is, in a passenger's getting on/off direction and in an upward direction, and wherein displacement of the combplate can be detected by a single detecting switch, thus the combplate safety device can be of a simple configuration and can achieve an improved safety performance.
2. Description of the Related Art
In a conventional passenger conveyor such as an escalator 1 or a moving walk shown in FIG. 9, a number of passenger platforms or steps 2 are endlessly connected to each other and are driven by driving chains not shown. Handrails 4 mounted on an outer periphery of a balustrade 3 provided on both right and left sides of the passenger step running path are driven in a synchronizing manner with the passenger steps 2. In this way, a passenger get on the step from a landing 5L on a lower floor is conveyed to a landing 5U on an upper floor.
Landing plates 5a provided at the landings 5L and 5U have combplates 6U, 6L, respectively, in order to prevent the passenger from stumbling over the landing plates 5a, or from having his or her foot caught in a clearance between the passenger steps 2 and the landing plate 5a, when the passenger on the passenger steps 2 gets off therefrom on the landing plates 5a. 
Each combplate 6U, 6R has a comb teeth 6a at its tip which is slidably meshing with a cleat 2a provided on the upper surface of the passenger steps 2. Thus, passenger's leg or a foreign object is scooped up so as not to be caught in the clearance.
For the safety, the combplates 6U, 6L are formed of a synthetic resin so that they are easily deformed or broken when the passenger's leg or the foreign object is caught in the clearance and an excessive external load is applied to the combplates 6U, 6R.
As shown in FIG. 10, a safety device for a passenger conveyor has been known, in which a thin detecting bar 7 horizontally extending in a width direction (a direction perpendicular to the drawing sheet) of the passenger step 2 is disposed near under the surface of the combplates 6U, 6R. When the deformed or broken combplates 6U, 6L or passenger's leg contact the detecting bar 7 and displace the same in an getting off direction, a safety switch is actuated to immediately stop the operation of the escalator 1 (See Japanese Patent Publication No. 150987/1986).
Another safety device for a passenger conveyor is known in which a sub-combplate is provided on the combplate such that it can move in a passenger's getting off direction and can swing in a vertical direction, to immediately stop the operation of the passenger conveyor when a displacement of the sub-combplate is detected. (See Japanese Patent Publication No. 73170/1996).
Further, a safety device for a passenger conveyor is known in which the operation of the passenger conveyor is immediately stopped when a detecting switch is actuated by a combplate which is displaced upward by passenger's leg or a foreign object caught in the clearance (See Japanese Patent Publication No. 171457/1999).
However, above mentioned conventional safety devices for a passenger conveyor have many disadvantages as follows.
That is, in the safety device disclosed in the Japanese Patent Publication No. 150987/1986, the combplates 6U, 6R must be formed of a synthetic resin, such that the combplates 6U, 6R are readily broken when an excessive force is applied thereto upon passenger's leg being caught in a clearance between the passenger step 2 and the combplates 6U, 6L. Thus, a combplate formed of an aluminum alloy having an excellent strength and durability can not be used.
In the safety device disclosed in the Japanese Patent Publication No. 73170/1996, a switch for detecting the displacement of the assisting combplate plate in a passenger's getting off direction and a switch for detecting an upward swing of the sub-combplate plate must be separately provided. Thus, these switches complicate the configuration of this safety device.
In the safety device disclosed in the Japanese Patent Publication No. 171457/1999, the operation of the escalator is stopped when a detecting switch is actuated by an upward displacement of the combplate plate. However, since a displacement of the combplate plate in a passenger's getting off direction is not detected, there is a room for further improving the safety performance of this safety device.